Gallstones

Gallstones form when liquid stored in the gallbladder hardens into pieces of stone-like material. The liquid, called bile, is used to help the body digest fats. Bile is made in the liver, then stored in the gallbladder until the body needs to digest fat. At that time, the gallbladder contracts and pushes the bile into a tube—called the common bile duct—that carries it to the small intestine, where it helps with digestion.

Bile contains water, cholesterol, fats, bile salts, proteins, and bilirubin. Bile salts break up fat, and bilirubin gives bile and stool a yellowish color. If the liquid bile contains too much cholesterol, bile salts, or bilirubin, under certain conditions it can harden into stones.

The two types of gallstones are cholesterol stones and pigment stones. Cholesterol stones are usually yellow-green and are made primarily of hardened cholesterol. They account for about 80 percent of gallstones. Pigment stones are small, dark stones made of bilirubin. Gallstones can be as small as a grain of sand or as large as a golf ball. The gallbladder can develop just one large stone, hundreds of tiny stones, or almost any combination.

The gallbladder and the ducts that carry bile and other digestive enzymes from the liver, gallbladder, and pancreas to the small intestine are called the biliary system.

Gallstones can block the normal flow of bile if they lodge in any of the ducts that carry bile from the liver to the small intestine. That includes the hepatic ducts, which carry bile out of the liver; the cystic duct, which takes bile to and from the gallbladder; and the common bile duct, which takes bile from the cystic and hepatic ducts to the small intestine. Bile trapped in these ducts can cause inflammation in the gallbladder, the ducts, or, rarely, the liver. Other ducts open into the common bile duct, including the pancreatic duct, which carries digestive enzymes out of the pancreas. If a gallstone blocks the opening to that duct, digestive enzymes can become trapped in the pancreas and cause an extremely painful inflammation called gallstone pancreatitis.

If any of these ducts remain blocked for a significant period of time, severe—possibly fatal—damage or infections affecting the gallbladder, liver, or pancreas can occur. Warning signs of a serious problem are fever, jaundice, and persistent pain.

Symptoms

Symptoms of gallstones are often called a gallstone "attack" because they occur suddenly. A typical attack can cause

• steady pain in the upper abdomen that increases rapidly and lasts from 30 minutes to several hours
• pain in the back between the shoulder blades
• pain under the right shoulder
• nausea or vomiting

Gallstone attacks often follow fatty meals, and they may occur during the night. Other gallstone symptoms include

• abdominal bloating
• recurring intolerance of fatty foods
• colic
• belching
• gas
• indigestion

People who also have the above and any of following symptoms should see a doctor right away:

• chills
• low-grade fever
• yellowish color of the skin or whites of the eyes
• clay-colored stools

Many people with gallstones have no symptoms. These patients are said to be asymptomatic, and these stones are called "silent stones." They do not interfere with gallbladder, liver, or pancreas function, and do not need treatment.

Diagnosis

Many gallstones, especially silent stones, are discovered by accident during tests for other problems. But when gallstones are suspected to be the cause of symptoms, the doctor is likely to do an ultrasound exam. Ultrasound uses sound waves to create images of organs. Sound waves are sent toward the gallbladder through a handheld device that a technician glides over the abdomen. The sound waves bounce off the gallbladder, liver, and other organs such as a pregnant uterus, and their echoes make electrical impulses that create a picture of the organ on a video monitor. If stones are present, the sound waves will bounce off them, too, showing their location. Ultrasound is the most sensitive and specific test for gallstones.

Other tests may also be used.

• Computed tomography (CT) scan may show the gallstones or complications.
• Magnetic resonance cholangiogram may diagnose blocked bile ducts.
• Cholescintigraphy (HIDA scan) is used to diagnose abnormal contraction of the gallbladder or obstruction. The patient is injected with a radioactive material that is taken up in the gallbladder, which is then stimulated to contract.
• Endoscopic retrograde cholangiopancreatography (ERCP). The patient swallows an endoscope—a long, flexible, lighted tube connected to a computer and TV monitor. The doctor guides the endoscope through the stomach and into the small intestine. The doctor then injects a special dye that temporarily stains the ducts in the biliary system. ERCP is used to locate and remove stones in the ducts.
• Blood tests. Blood tests may be used to look for signs of infection, obstruction, pancreatitis, or jaundice.

Gallstone symptoms are similar to those of heart attack, appendicitis, ulcers, irritable bowel syndrome, hiatal hernia, pancreatitis, and hepatitis. So accurate diagnosis is important.

Causes

Cholesterol Stones

Scientists believe cholesterol stones form when bile contains too much cholesterol, too much bilirubin, or not enough bile salts, or when the gallbladder does not empty as it should for some other reason.

Pigment Stones

The cause of pigment stones is uncertain. They tend to develop in people who have cirrhosis, biliary tract infections, and hereditary blood disorders, such as sickle cell anemia, in which too much bilirubin is formed.

Reference:

National Digestive Diseases Information Clearinghouse, USA.